The Experience of Audiometric Measurement for the Shinkansen Railroad Conductors

Abstract

In 1975, 530 conductors on working for the Shinkansen railroad were studied by questionares referring to deafness, tinnitus and fullness in the ears. The hearing of 37 persons with one or other complaints were measured by an audiometer, but the hearing of 15 persons among them were normal. It was found that the results of study on hearing impairment by questionare contained about 50% false positive.
The audiogram of the hearing impaired did not showed hearing loss at frequencies under 2, 000 Hz.
The hearing loss over 25dB at 4, 000Hz were recognized in 14 persons. The audiogram of 5 persons among them showed C₅ dip.
The rate of hearing impairment over 21dB=C₄+2C₅+C₆/4 tested by us was 0.19% which was less than the results (3.5%) obtained by Kubo in 1963 concerning to hearing impairment in the railroad conductors.
The hearing impairment showed by us might be caused by noise in passenger coach in Shinkansen railroad, it might also be accelerated by working in Shinkansen railroad after they exposed to noise in working, as former railroad conductros in a certain period of time.